Tub for washing machines

ABSTRACT

Disclosed herein is a tub for washing machines. The tub comprises a tub body, a weight receiving part formed at the tub body, and a balance weight integrally formed at the weight receiving part by injection molding. Consequently, the balance weight is integrally attached to the tub body without using additional fixing units for fixing the balance weight to the tub body, and therefore, the balance weight and the tub body are formed in a simple structure.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tub for washing machines, and, more particularly, to a tub for washing machines having a balance weight integrally formed at the tub, which eliminates the necessity of providing additional fixing units for fixing the balance weight to the tub, whereby the tub and the balance weight are formed in a simple structure.

2. Description of the Related Art

Generally, a washing machine is a machine that removes contaminants from clothes or bedclothes (hereinafter referred to as “laundry”) received in a drum using interaction of water and detergent. The washing machine performs washing, rinsing, spin-drying, and drying operations in succession to clean the laundry.

FIG. 1 is a sectional view illustrating an example of a drum type washing machine 1 with a conventional tub mounted therein, and FIG. 2 is a perspective view of the conventional tub of FIG. 1 illustrating a balance weight mounted at the conventional tub.

As shown in FIGS. 1 and 2, the conventional drum type washing machine 1 comprises: a cabinet 2 forming the outer appearance of the drum type washing machine 1; a tub 8 horizontally mounted in the cabinet 2 such that impact and vibration generated from the tub 8 are effectively absorbed by springs 4 and a damper 6; a drum 10 rotatably disposed in the tub 8 for washing laundry placed therein; a plurality of lifters 12 attached to the inside surface of the drum 10 for lifting the laundry to a predetermined height, when the drum 10 is rotated, such that the laundry falls from the predetermined height due to gravity; and a motor 18 mounted at the rear of the tub 8, the motor 18 being connected to a rotary shaft of the drum 10 via pulleys 14 and a belt 16.

At the front surface of the cabinet 2 is mounted a cabinet cover 22 having a laundry inlet/outlet hole 20 formed at the center thereof such that laundry can be put into or removed from the drum 10 through the laundry inlet/outlet hole 20. To the cabinet cover 22 is hingedly connected a door 24 for opening or closing the laundry inlet/outlet hole 20.

At the upper end of the cabinet cover 22 is mounted a control panel 28 having electric field parts 26 for controlling the operation of the drum type washing machine 1 mounted therein. Between the laundry inlet/outlet hole 20 and the inlet of the tub 8 is disposed a gasket 29 for reducing impact generated when the drum 10 is rotated and serving as a packing member for preventing leakage of washing water.

In addition, a balance weight 30 is attached to the front part of the tub 8 for eliminating unbalance in weight of the tub 8 due to the pulleys 14, the belt 16, and the motor 18.

The balance weight 30 is a heavy weight member, such as a concrete material or iron, which is injected into a mold and then hardened. The balance weight 30 is disposed along the front edge part of the tub 8. The balance weight 30 is securely fixed to the front edge part of the tub 8 by means of fixing units 32.

Each of the fixing units 32 comprises: a fixing boss 34 protruded forward from the front edge part of the tub 8; a through-hole 36 formed at the balance weight 30 such that the fixing boss 34 is inserted through the through-hole 36; and a fixing bolt 38 threadedly engaged with the fixing boss 34 for securely fixing the balance weight 30 to the front surface of the tub 8.

When laundry is put into the drum 10 of the drum type washing machine with the above-stated construction, and the drum type washing machine is operated, a rotating force of the motor 18 is transmitted to the drum 10 via the pulleys 14 and the belt 16, and therefore, the drum 10 is rotated. During the rotation of the drum 10, washing, rinsing, and spin-drying operations are performed in succession. At this time, back-and-forth, right-and-left, and up-and-down vibration is generated at the tub 8 due to the operation of the motor 18 and the drum 10. The vibration of the tub 8 is absorbed by elastic force of the springs 4 and damping force of the damper 6.

However, the conventional drum type washing machine with the above-stated construction has the following problems.

The balance weight 30 is separately manufactured, and is then attached to the front surface of the tub 8 by means of the fixing units 32. As a result, the number of parts is increased, and the manufacturing costs of the parts are increased. Furthermore, the balance weight attaching process is complicated.

Furthermore, the fixing bosses 34 of the fixing units 32 may be damaged due to the vibration of the tub 8 while the drum type washing machine 1 is operated, and therefore, the balance weight 30 may be accidentally separated from the tub 8.

Meanwhile, the tub 8 is vibrated back and forth, right and left, and up and down in the cabinet 2 while the drum type washing machine 1 is operated. For this reason, the drum type washing machine 1 is designed such that there is provided sufficient space around the tub 8 in order to prevent collision of the tub 8 with the cabinet 2.

In the drum type washing machine 1, however, the provision of sufficient space between the tub 8 and the cabinet cover 22 is difficult due to the balance weight 30. If sufficient space is provided between the tub 8 and the cabinet cover 22, the size of the drum type washing machine 1 is increased.

FIG. 3 is a sectional view illustrating another example of a drum type washing machine 40 with a conventional tub mounted therein. The drum type washing machine 40 shown in FIG. 3 is a drum type washing machine with drying function that is capable of performing washing, rinsing, spin-drying, and drying operations in succession.

It should be noted that the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings.

The conventional drum type washing machine with drying function 40 comprises: a control panel 41 mounted at the top of the washing machine; a drying duct 44 disposed on the tub 8 while one end of the drying duct 44 communicates with the upper part of the gasket 29, the drying duct 44 having a heater 42 and a blower 43 mounted therein; and a condensing duct 46, having one end connected to the lower part of the rear surface of the tub 8 and the other end connected to the other end of the drying duct 44, for condensing moisture contained air circulating in the washing machine. Other components of the drum type washing machine with drying function 40 are identical in construction and operation to those of the previously described drum type washing machine 1, and therefore, a detailed description thereof will not be given.

The air condensed in the condensing duct 46 is blown by the blower 43 and heated by the heater 42. As a result, the condensed air is changed into hot wind. The hot wind is supplied into the drum 10 through one end of the drying duct 44 to dry the laundry received in the drum 10.

In the conventional drum type washing machine with drying function 40, however, one end of the drying duct 44 as well as the balance weight 30 is disposed between the tub 8 and the cabinet cover 22. Consequently, the provision of an installation space for the drying duct 44 and the balance weight 30 is much more difficult.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a tub for washing machines having a balance weight integrally formed at the outer circumferential surface of the tub, which eliminates the necessity of providing additional fixing units for fixing the balance weight to the tub, whereby the tub and the balance weight are formed in a simple structure.

It is another object of the present invention to provide a tub for washing machines wherein the height of the balance weight protruded forward from the front surface of the tub is reduced, and therefore, the provision of space between the tub and a cabinet cover is easily accomplished, and increase in size of the drum type washing machine due to the balance weight is prevented.

In accordance with the present invention, the above and other objects can be accomplished by the provision of a tub for washing machines, comprising: a tub body; a weight receiving part formed at the tub body; and a balance weight integrally formed at the weight receiving part by injection molding.

Preferably, the balance weight is made of a concrete material or a metal material having a low melting point.

Preferably, the tub body comprises: a front tub having an inlet formed at the front surface thereof and the rear surface of which is opened; and a rear tub attached to the rear surface of the front tub, the weight receiving part being formed at the front tub and/or the rear tub.

Preferably, the weight receiving part is formed at the outer circumferential surface of the tub body.

Preferably, the weight receiving part is defined by ribs protruded from the tub body.

Preferably, the weight receiving part comprises: a vertical rib protruded outward from the outer circumferential surface of the tub body while the vertical rib is perpendicular to the outer circumferential surface of the tub body; and a horizontal rib formed at the tip end of the vertical rib while the horizontal rib is parallel with the outer circumferential surface of the tub body.

Preferably, the weight receiving part is formed along the outer circumference of the tub body.

Preferably, the weight receiving part comprises: a vertical rib protruded outward from the outer circumferential surface of the tub body along the outer circumference of the tub body while the vertical rib is perpendicular to the outer circumferential surface of the tub body; and a horizontal rib protruded forward or rearward from the tip end of the vertical rib while the horizontal rib is parallel with the outer circumferential surface of the tub body.

Preferably, the tub body is mounted in a cabinet in a shock-absorbing fashion, and the weight receiving part has collapsed sections, which are opposite to both side surfaces of the cabinet, the collapsed sections being collapsed toward the tub body.

Preferably, the horizontal rib is protruded from the tip end of the vertical rib further forward than the front surface of the tub body.

Preferably, the tub body is provided at the front surface thereof with an inlet, and the tub further comprises: a cylindrical rib disposed at the inlet of the tub body while the cylindrical rib is protruded forward from the tub body.

Preferably, the tub further comprises: a curling part formed at the tip end of the cylindrical rib, to which a gasket is connected, and the gasket is disposed between the inlet of the tub body and a laundry inlet/outlet hole of a cabinet cover disposed in front of the tub body.

Preferably, the balance weight comprises: a first weight disposed between the vertical and horizontal ribs and the outer circumferential surface of the tub body; and a second weight disposed between the vertical and cylindrical ribs and the front surface of the tub body, the second weight being integrally molded with the first weight.

Preferably, the tub further comprises: at least one motion preventing protrusion protruded from the front surface of the tub body for preventing motion of the balance weight.

Preferably, the at least one motion preventing protrusion is provided at the tip end thereof with a separation preventing extension for preventing the balance weight from being separated from the tub body.

Preferably, the at least one motion preventing protrusion comprises a plurality of motion preventing protrusions arranged at the front surface of the tub body in the circumferential direction while being spaced apart from one another.

According to the present invention, the balance weight is injected into the weight receiving part formed at one side of the tub body, and is then hardened in the weight receiving part. As a result, the balance weight is integrally attached to the tub body, which eliminates the necessity of providing additional fixing units for fixing the balance weight to the tub body, and therefore, the balance weight and the tub are formed in a simple structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a sectional view illustrating an example of a drum type washing machine with a conventional tub mounted therein;

FIG. 2 is a perspective view of the conventional tub of FIG. 1 illustrating a balance weight mounted at the conventional tub;

FIG. 3 is a sectional view illustrating another example of a drum type washing machine with a conventional tub mounted therein;

FIG. 4 is a sectional view illustrating a drum type washing machine with a tub according to a first preferred embodiment of the present invention mounted therein;

FIG. 5 is a perspective view illustrating a tub body of the tub for drum type washing machines according to the first preferred embodiment of the present invention;

FIG. 6 is a perspective view illustrating the tub for drum type washing machines according to the first preferred embodiment of the present invention;

FIG. 7 is a sectional view illustrating a drum type washing machine with a tub according to a second preferred embodiment of the present invention mounted therein;

FIG. 8 is a perspective view illustrating the tub for drum type washing machines according to the second preferred embodiment of the present invention;

FIG. 9 is a sectional view illustrating a drum type washing machine with a tub according to a third preferred embodiment of the present invention mounted therein; and

FIG. 10 is a perspective view illustrating the tub for drum type washing machines according to the third preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a sectional view illustrating a drum type washing machine 50 with a tub according to a first preferred embodiment of the present invention mounted therein, FIG. 5 is a perspective view illustrating a tub body of the tub for drum type washing machines according to the first preferred embodiment of the present invention, FIG. 6 is a perspective view illustrating the tub for drum type washing machines according to the first preferred embodiment of the present invention.

As shown in FIGS. 4 to 6, the drum type washing machine 50 according to the first preferred embodiment of the present invention comprises: a cabinet 52 forming the outer appearance of the drum type washing machine 50; a tub body 58 horizontally mounted in the cabinet 52 such that impact and vibration generated from the tub 8 are effectively absorbed by springs 54 and a damper 56; a drum 60 rotatably disposed in the tub body 58 for washing laundry placed therein; a plurality of lifters 62 attached to the inside surface of the drum 60 for lifting the laundry to a predetermined height, when the drum 60 is rotated, such that the laundry falls from the predetermined height due to gravity; a motor 68 mounted at the rear of the tub body 58, the motor 68 being connected to a rotary shaft of the drum 60 via pulleys 64 and a belt 66; and a balance weight 80 integrally formed at the tub body 58 for eliminating unbalance in weight of the tub body 58.

At the front surface of the cabinet 52 is mounted a cabinet cover 72 having a laundry inlet/outlet hole 70, through which laundry can be put into or removed from the drum 60. To the cabinet cover 72 is hingedly connected a door 74 for opening or closing the laundry inlet/outlet hole 70.

At the upper end of the cabinet cover 72 is mounted a control panel 78 having electric field parts 76 for controlling the operation of the drum type washing machine 50 mounted therein. Between the laundry inlet/outlet hole 70 and the inlet of the tub body 58 is disposed a gasket 79 for reducing impact generated when the drum 60 is rotated and serving as a packing member for preventing leakage of washing water.

At the outer circumferential surface of the tub body 58 is formed a weight receiving part 90, in which the balance weight 80 is received by injection molding such that unbalance in weight of the tub body 58 due to the pulleys 64, the belt 66, the motor 68, and other parts is eliminated by the balance weight 80.

The tub body 58 comprises: a front tub 58A having an inlet formed at the front surface thereof and the rear surface of which is opened; and a rear tub 58B attached to the rear surface of the front tub 58A and the front surface of which is opened. Preferably, the weight receiving part 90 is formed at the front tub 58A and/or the rear tub 58B.

In the following description, the weight receiving part 90 is formed at the front tub 58A.

At the inlet of the front tub 58A is formed a curling part 59A, to which the gasket 79 is connected. The curling part 59A is bent in such a manner that the curling part 59A is protruded forward a predetermined height from the inlet of the front tub 58A and is then extended outward.

The balance weight 80 is a heavy weight member, such as a concrete material or a metal material. Preferably, the metal material has a low melting point. Specifically, the balance weight 80 is injected into the weight receiving part 90 in a fluid state, and is then hardened in the weight receiving part 90. As a result, the balance weight 80 is integrally attached to the tub body 58.

Meanwhile, the weight receiving part 90 is formed at the outer circumferential surface of the front tub 58A in the shape of a rib. Also, the weight receiving part 90 is formed along the outer circumference of the front tub 58A.

Specifically, the weight receiving part 90 comprises: a vertical rib 92 protruded outward from the outer circumferential surface of the front tub 58A along the outer circumference of the front tub 58A while the vertical rib 92 is perpendicular to the outer circumferential surface of the front tub 58A; and a horizontal rib 93 protruded forward or rearward from the tip end of the vertical rib 92 while the horizontal rib 93 is parallel with the outer circumferential surface of the front tub 58A.

The balance weight 80 is injected into the space defined between the vertical and horizontal ribs 92 and 93 and the outer circumferential surface of the front tub 58A, and is then hardened in the space. As a result, the ring-shaped balance weight 80 is integrally attached along the outer circumferential surface of the front tub 58A.

The weight receiving part 90 has collapsed sections 94, which are opposite to both side surfaces of the cabinet 52. Specifically, the collapsed sections 94 of the weight receiving part 90 are collapsed toward the tub body 58 to prevent collision of the tub body 58 and the cabinet 52.

The collapsed sections 94 of the weight receiving part 90 are vertically arranged such that the collapsed sections 94 of the weight receiving part 90 are parallel with the side surfaces of the cabinet 52.

The manufacturing process, operation, and effects of the tub for drum type washing machines with the above-stated construction according to the first preferred embodiment will be described hereinafter in detail.

First, the front tub 58A is molded through injection molding of synthetic resin such that the weight receiving part 90 is formed at the outer circumferential surface of the front tub 58A along the outer circumference of the front tub 58A. Similarly, the rear tub 58B is also molded through injection molding of synthetic resin.

The opened front surface of the rear tub 58B is connected to the opened rear surface of the front tub 58A. As a result, the tub body 58 is completed.

A concrete material or a metal material having a low melting point is injected into the weight receiving part 90 of the completed tub body 58 in a fluid state, and is then hardened in the weight receiving part 90. As a result, the balance weight 80 is integrally attached to the front tub 58A along the outer circumferential surface of the front tub 58A.

Specifically, the balance weight 80 is formed in the shape of a ring, which surrounds the outer circumferential surface of the front tub 58A.

Consequently, the balance weight 80 is stably and securely attached to the tub body without the provision of additional fixing units. Furthermore, the molding process of the balance weight 80 and the fixing process of the balance weight 80 are simultaneously performed, and therefore, the assembly of the tub body 58 and the balance weight 80 is easily accomplished.

When the drum type washing machine 50 with the tub, to which the balance weight is integrally attached, mounted therein is operated, an appropriate amount of washing water is supplied into the tub body 58, and a rotating force of the motor 68 is transmitted to the drum 60 via the pulleys 64 and the belt 66, and therefore, the drum 60 is rotated. During the rotation of the drum 60, washing, rinsing, and spin-drying operations of laundry placed in the drum 60.

As the motor 68 and the drum 60 are rotated as described above, the tub body 58 is vibrated back and forth, right and left, and up and down. However, the vibration of the tub body 58 is absorbed by elastic force of the springs 54 and damping force of the damper 56.

According to the present invention, the balance weight is not disposed at the front surface of the tub body 58, which is distinguished from the conventional art. Consequently, the provision of sufficient space between the tub body 58 and the cabinet cover 72 is easily accomplished.

Since the sufficient space is provided between the tub body 58 and the cabinet cover 72, the collision of the front surface of the tub body 58 and the cabinet cover 72 due to the vibration of the tub body 58 is effectively prevented. In the case of the drum type washing machine with drying function, the drying duct is easily disposed between the tub body 58 and the cabinet cover 72.

Although the weight receiving part 90 and the balance weight 80 are disposed along the outer circumferential surface of the front tub 58A, the collapsed sections 94 of the weight receiving part 90 and the balance weight 80 are collapsed toward the tub body 58. Consequently, the provision of space between the tub body 58 and the cabinet cover 52 is easily accomplished.

Specifically, the height of the collapsed sections 94 of the weight receiving part 90 and the balance weight 80 from the tub body 58 is lower than that of other sections of the weight receiving part 90 and the balance weight 80 from the tub body 58. Consequently, the distance between the opposite side surfaces of the cabinet 52 and the tub body 58 is not greatly decreased.

FIG. 7 is a sectional view illustrating a drum type washing machine with a tub according to a second preferred embodiment of the present invention mounted therein, and FIG. 8 is a perspective view illustrating the tub for drum type washing machines according to the second preferred embodiment of the present invention.

Components of the second preferred embodiment of the present invention, which are identical or similar in construction to those of the first preferred embodiment of the present invention, are indicated by the same reference numerals as those of the first preferred embodiment of the present invention, and a detailed description thereof will not be given.

As shown in FIGS. 7 and 8, the tub for drum type washing machines according to the second preferred embodiment of the present invention is characterized by a tub body 58, which comprises: a front tub 58A having an inlet formed at the front surface thereof and the rear surface of which is opened; and a rear tub 58B attached to the rear surface of the front tub 58A and the front surface of which is opened, and a cylindrical rib 59 disposed around the inlet of the front tub 58A while the cylindrical rib 59 is protruded forward a predetermined height from the front tub 58A.

At the tip end of the cylindrical rib 59 is formed a curling part 59A, to which a gasket 79 is connected. The curling part 59A is bent in such a manner that the curling part 59A is extended outward.

The tub for drum type washing machines according to the second preferred embodiment of the present invention is also characterized by a weight receiving part 96 comprising: a vertical rib 97 protruded outward from the outer circumferential surface of the front tub 58A along the outer circumference of the front tub 58A while the vertical rib 92 is perpendicular to the outer circumferential surface of the front tub 58A; and a horizontal rib 98 formed such that the horizontal rib 98 is protruded from the tip end of the vertical rib 97 further forward than the front surface of the front tub 58A while the horizontal rib 98 is parallel with the outer circumferential surface of the front tub 58A.

Furthermore, the tub for drum type washing machines according to the second preferred embodiment of the present invention is characterized by a balance weight 82 comprising: a first weight 84 disposed between the vertical and horizontal ribs 97 and 98 and the outer circumferential surface of the front tub 58A; and a second weight 86 disposed between the vertical and cylindrical ribs 97 and 59 and the front surface of the front tub 58A, the second weight 86 being integrally molded with the first weight 84.

Other components of the tub for drum type washing machines according to the second preferred embodiment except the cylindrical rib 59, the weight receiving part 96, and the balance weight 82 are identical in construction to those of the tub for drum type washing machines according to the first preferred embodiment.

The manufacturing process of the tub for drum type washing machined with the above-stated construction according to the second preferred embodiment will be described below. The balance weight 82 is injected into the weight receiving part 96 in a fluid state until the balance weight 82 is filled up to between the tip end of the horizontal rib 98 and the cylindrical rib 59 of the front tub 58A, and is then hardened in the weight receiving part 96. As a result, the balance weight 82 covers the front surface of the front tub 58A.

At this time, the thickness of the second weight 86 disposed at the front surface of the front tub 58A is smaller than that of the first weight 84 disposed at the outer circumferential surface of the front tub 58A. Consequently, the provision of space between the balance weight 82 and the cabinet cover 72 is easily accomplished.

According to the second preferred embodiment, the balance weight 82 is more stably attached to the tub body 58, and the weight of the balance weight 82 is more greatly increased.

FIG. 9 is a sectional view illustrating a drum type washing machine with a tub according to a third preferred embodiment of the present invention mounted therein, and FIG. 10 is a perspective view illustrating the tub for drum type washing machines according to the third preferred embodiment of the present invention.

Components of the third preferred embodiment of the present invention, which are identical or similar in construction to those of the second preferred embodiment of the present invention, are indicated by the same reference numerals as those of the second preferred embodiment of the present invention, and a detailed description thereof will not be given.

As shown in FIGS. 9 and 10, the tub for drum type washing machines according to the third preferred embodiment of the present invention is characterized by motion preventing protrusions 100 protruded from the front surface of the front tub 58A for preventing motion of the balance weight 82 received in the weight receiving part 96. Other components of the tub for drum type washing machines according to the third preferred embodiment are identical in construction to those of the tub for drum type washing machines according to the second preferred embodiment.

Specifically, the motion preventing protrusions 100 are protruded forward from the front surface of the front tub 58A, on which the balance weight 82 is disposed. The motion preventing protrusions 100 are arranged at the front surface of the front tub 58A in the circumferential direction while being spaced apart from one another.

At each of the tip ends of the motion preventing protrusions 100 is formed a separation preventing extension 102 for preventing the balance weight 82 from being separated from the front tub 58A. Specifically, the balance weight 82 is caught by the separation preventing extensions 102 such that the balance weight is not separated from the front tub 58A.

As a result, the up-and-down and right-and-left motion and the circumferential rotation of the balance weight 82 is effectively prevented by the motion preventing protrusions 100, and the back-and-forth motion of balance weight 82 is effectively prevented by the separation preventing extensions 102.

Consequently, the balance weight 82 is more securely and stably attached to the tub body 58 by means of the motion preventing protrusions 100 having the separation preventing extensions 102.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

For example, the weight receiving part may be formed at the upper part or the lower part of the tub body based on design conditions of the tub body. Alternatively, the weight receiving part may be partially formed at the side part of the tub body. Furthermore, the weight receiving part may be formed in the shape of a box having an injection port defined by the vertical rib and the horizontal rib.

As apparent from the above description, the tub for washing machines according to the present invention has the following effects.

The balance weight is injected into the weight receiving part formed at one side of the tub body, and is then hardened in the weight receiving part. As a result, the balance weight is integrally attached to the tub body, which eliminates the necessity of providing additional fixing units for fixing the balance weight to the tub body, and therefore, the balance weight and the tub are formed in a simple structure.

Since the balance weight is integrally attached to the tub body, and therefore, the necessity of providing the fixing units for fixing the balance weight to the tub body is eliminated, the number of parts is decreased, the manufacturing process of the parts is simplified, and the manufacturing costs of the parts are decreased. Especially, accidental separation of the balance weight from the tub body due to damage to the fixing units is effectively prevented.

Moreover, the weight receiving part is formed at the outer circumferential surface of the tub body along the outer circumference of the tub body. As a result, the balance weight is disposed such that the balance weight surrounds the outer circumferential surface of the tub body. Consequently, the rigidity of the tub body due to the balance weight is increased, and therefore, deformation of the tub body or damage to the tub body is effectively prevented.

In addition, the balance weight is integrally molded between the weight receiving part and the tub body, and the motion preventing protrusions, which are provided at the tip ends thereof with the separation preventing extensions, respectively, are protruded forward from the front surface of the tub body. Consequently, the motion of the balance weight and separation of the balance weight from the tub body are effectively prevented.

Furthermore, the provision of space between the tub body and the cabinet cover is easily accomplished, and therefore, the collision of the tub body and the cabinet cover is effectively prevented. Consequently, vibration-preventing design of the drum type washing machine is more easily accomplished. Especially, the present invention is very useful when a drum type washing machine with drying function having a drying duct disposed in front of the tub body is designed. Also, increase in size of the drum type washing machine is prevented. 

1. A tub for washing machines, comprising: a tub body; a weight receiving part formed at the tub body; and a balance weight integrally formed at the weight receiving part by injection molding.
 2. The tub as set forth in claim 1, wherein the balance weight is made of a concrete material or a metal material having a low melting point.
 3. The tub as set forth in claim 1, wherein the tub body comprises: a front tub having an inlet formed at the front surface thereof and the rear surface of which is opened; and a rear tub attached to the rear surface of the front tub, the weight receiving part being formed at the front tub and/or the rear tub.
 4. The tub as set forth in claim 1, wherein the weight receiving part is formed at the outer circumferential surface of the tub body.
 5. The tub as set forth in claim 4, wherein the weight receiving part is defined by ribs protruded from the tub body.
 6. The tub as set forth in claim 5, wherein the weight receiving part comprises: a vertical rib protruded outward from the outer circumferential surface of the tub body while the vertical rib is perpendicular to the outer circumferential surface of the tub body; and a horizontal rib formed at the tip end of the vertical rib while the horizontal rib is parallel with the outer circumferential surface of the tub body.
 7. The tub as set forth in claim 5, wherein the weight receiving part is formed along the outer circumference of the tub body.
 8. The tub as set forth in claim 7, wherein the weight receiving part comprises: a vertical rib protruded outward from the outer circumferential surface of the tub body along the outer circumference of the tub body while the vertical rib is perpendicular to the outer circumferential surface of the tub body; and a horizontal rib protruded forward or rearward from the tip end of the vertical rib while the horizontal rib is parallel with the outer circumferential surface of the tub body.
 9. The tub as set forth in claim 8, wherein the horizontal rib is protruded from the tip end of the vertical rib further forward than the front surface of the tub body.
 10. The tub as set forth in claim 9, wherein the tub body is provided at the front surface thereof with an inlet, and the tub further comprises: a cylindrical rib disposed at the inlet of the tub body while the cylindrical rib is protruded forward from the tub body.
 11. The tub as set forth in claim 10, further comprising: a curling part formed at the tip end of the cylindrical rib, to which a gasket is connected, wherein the gasket is disposed between the inlet of the tub body and a laundry inlet/outlet hole of a cabinet cover disposed in front of the tub body.
 12. The tub as set forth in claim 10, wherein the balance weight comprises: a first weight disposed between the vertical and horizontal ribs and the outer circumferential surface of the tub body; and a second weight disposed between the vertical and cylindrical ribs and the front surface of the tub body, the second weight being integrally molded with the first weight.
 13. The tub as set forth in claim 12, further comprising: at least one motion preventing protrusion protruded from the front surface of the tub body for preventing motion of the balance weight.
 14. The tub as set forth in claim 13, wherein the at least one motion preventing protrusion is provided at the tip end thereof with a separation preventing extension for preventing the balance weight from being separated from the tub body.
 15. The tub as set forth in claim 14, wherein the at least one motion preventing protrusion comprises a plurality of motion preventing protrusions arranged at the front surface of the tub body in the circumferential direction while being spaced apart from one another.
 16. The tub as set forth in claim 8, wherein the tub body is mounted in a cabinet in a shock-absorbing fashion, and the weight receiving part has collapsed sections, which are opposite to both side surfaces of the cabinet, the collapsed sections being collapsed toward the tub body.
 17. The tub as set forth in claim 16, wherein the tub body is provided at the front surface thereof with an inlet, and the tub further comprises: a cylindrical rib disposed at the inlet of the tub body while the cylindrical rib is protruded forward from the tub body.
 18. The tub as set forth in claim 17, wherein the balance weight comprises: a first weight disposed between the vertical and horizontal ribs and the outer circumferential surface of the tub body; and a second weight disposed between the vertical and cylindrical ribs and the front surface of the tub body, the second weight being integrally molded with the first weight.
 19. The tub as set forth in claim 18, further comprising: at least one motion preventing protrusion protruded from the front surface of the tub body for preventing motion of the balance weight.
 20. The tub as set forth in claim 19, wherein the at least one motion preventing protrusion is provided at the tip end thereof with a separation preventing extension for preventing the balance weight from being separated from the tub body. 